Method and system for general packet radio service tunneling protocol (gtp) probing

ABSTRACT

Methods and systems for probing General Packet Radio System (GPRS) Tunneling Protocol (GTP) links in a communication network are disclosed. According to principles described herein, originator and responder nodes (endpoints) are configured to use a probing interval that can be changed dynamically to adapt the probing frequency to the prevailing conditions measured and/or capabilities available at the originator and/or the responder. According to a broad aspect, a method for a network node includes receiving a probing request message originating from a first peer node via a GTP link, the probing request message containing a request indication for a probing interval recommendation for probing the GTP link, in response to the probing request message received, determining a probing interval recommendation for probing the GTP link and sending a probing response message to the first peer node via the GTP link, the probing response message containing the probing interval recommendation determined.

TECHNICAL FIELD

The present invention relates generally to a General Packet Radio System(GPRS) Tunneling Protocol (GTP) performance monitoring and moreparticularly to the probing of GTP links in a network.

BACKGROUND

The General Packet Radio Service (GPRS) is a packet oriented mobile dataservice for cellular communications systems, such as Global System forMobile communications (GSM), Wideband Code Division Multiple Access(WCDMA), Universal Mobile Telecommunications System UMTS, LTE-Advanced(LTE-A) or other 4^(th) Generation (4G)) networks. Typically, in thesetypes of communication networks, the GPRS Tunneling Protocol (GTP) whichallows the creation of GTP-U tunnels is used to carry user data trafficbetween nodes. GTP-U is an Internet Protocol (IP) based communicationprotocol and, like other GTP protocols, runs over User Datagram Protocol(UDP) and IP transport layers. The control plane procedures to setup aGTP-U tunnel are defined in protocols such as GTP-C (another GTPprotocol), as well as the Radio Access Network Application Part (RANAP),S1-Application Protocol (S1-AP), X2 Application Protocol (X2-AP) and M3Application Protocol (M3AP).

As is well-known, a GTP-U node can support one or more GTP-U endpointswhere each pair of GTP-U endpoints defines a GTP-U path or link whichitself may carry multiple GTP-U tunnels. GTP-U tunnels carry GTP-U datapackets (also known as G-PDUs) between the GTP-U tunnel endpoints. Atunnel endpoint is identified by a tunnel identifier, e.g., a TunnelEndpoint IDentifier (TEID).

In addition to carrying GTP-U data packets, each pair of GTP-U endpointscan also exchange GTP-U signaling messages for user plane pathmanagement or for user plane tunnel management. An example of pathmanagement messages are GTP-U echo request and response messages. Thesemessages can be used by a GTP-U endpoint to determine if peer GTPendpoints are alive and/or reachable. Typically, if a peer endpoint doesnot respond after a specific number of echo request messages, the peerendpoint is declared down and all of the tunnels associated with thepeer endpoint are taken down. In conventional radio networks, echomessages are used to manage GTP paths established over an S1-U interfacebetween an eNodeB (eNB) and a Serving Gateway (S-GW) but not over X2-Uinterfaces between eNBs and M1 interfaces between Multimedia Broadcastand Multicast Services Gateway (MBMS-GW) and eNBs.

Currently, the amount of traffic carried over existing X2-U connections(e.g. X2 handover or packet forwarded traffic) is relatively small andnot usually delay sensitive. However, as new radio features are beingintroduced by network operators requiring greater coordination betweeneNBs but also between eNBs and Core Network (CN) nodes and networks, thetraffic over X2-U unicast, S1-U unicast and M1 multicast connections andother Internet Protocol (IP) based interfaces will undoubtedly increase.Such features, for example, Carrier Aggregation, Coordinated Multi-Point(CoMP) transmission/reception schemes and Cloud Radio Access Network(C-RAN) will also impose tighter delay and/or latency requirements onX2-U connections. Future evolutions of 4G or 5^(th) Generation (5G)networks are also envisioned to embrace a split baseband architecturewhere LTE baseband protocols (e.g. Packet Data Convergence Protocol(PDCP), Radio Link Control (RLC), Medium Access Control (MAC)) will runover interconnected IP nodes or interfaces supporting the GTP-U protocolbut with very low delay requirements there between.

In light of the above, knowledge of GTP link and/or tunnel performancecapabilities may help new radio feature deployment and inform networktraffic engineering, management and fault diagnosis functions to ensurethat requirements specified for connections between nodes or endpointsin a network are met and/or maintained. In other words, there is a needfor probing links to help ensure that the network can provide theQuality of Service (QoS) required.

Active IP probe based sampling of the IP path carrying the GTP-Utunneled traffic is currently used as a methodology for estimating theend-to-end state and performance of unicast and multicast subscriberconnections across an IP network. Examples of active IP probingtechniques include the One-Way Active Measurement Protocol (OWAMP) andthe Two-Way Active Measurement Protocol (TWAMP) both developed by theInternet engineering task force (IETF) standard body and described inRequest for Comments (RFC) documents 5357 and 4656 hereby incorporatedby reference in their entirety.

However, wireless network operators wanting to deploy these types of IPtest protocols must often purchase and manage additional equipment,separate from the equipment normally required to establish theirnetworks. Even when the equipment and functionality can be integratedinto certain nodes (e.g. eNBs, S-GWs and MBMS-GW), the test protocolsrequires the configuration of an extensive set of parameters (e.g. IPaddresses, UDP ports, IP QoS, test modes, etc.) before any IP testconnection can be established and in many instances, the configurationis static and does not change for the duration of a test connection. Inaddition, statically configuring parameters and correlating IP testconnections to nodes in a radio network can become a very onerous task,particularly as the number of IP connections and nodes in the networkbecomes large. Accordingly, there is a need for an improved probingtechnique.

SUMMARY

Methods and systems for enabling the collection of end to endperformance information of General Packet Radio System (GPRS) TunnelingProtocol (GTP) links in a communication network are disclosed. Accordingto principles described herein, originator and responder nodes/endpointsare configured for probing GTP links using a probing interval that canbe changed dynamically to adapt the probing frequency to the prevailingconditions measured and/or capabilities available at either theoriginator or the responder node. In some implementations, a dynamicprobing interval may be useful where, for example, the originator and/orthe responder is subject to performance variations (e.g. throughput orload) either at the link level or at the node level. By dynamicallyadjusting the probing interval, it may be possible for nodes/endpointsto adapt their ability to probe based on current conditions and/orcapabilities and hence optimize the probing such that the interferencewith each node's performance is reduced or minimized.

According to a broad aspect, there is provided a method for a networknode for probing GTP links operable to carry data traffic between thenetwork node and peer nodes in a communication network. The methodincludes at the network node receiving a probing request messageoriginating from a first peer node via a GTP link where the probingrequest message contains a request indication for a probing intervalrecommendation for probing the GTP link. The method also includes inresponse to the probing request message received, determining a probinginterval recommendation for probing the GTP link. The method alsoincludes sending a probing response message to the first peer node viathe GTP link where the probing response message contains the probinginterval recommendation.

In some embodiments, sending a probing response message includes sendinga number of successive probing response messages to the first peer nodewhere each successive probing response message contains the probinginterval recommendation determined. In other embodiments, the probingresponse message contains at least one parameter associated with one ofthe probing request message, the probing response message and the GTPlink.

In yet other embodiments, the probing interval recommendation is acurrent probing interval and the method further includes receiving asubsequent probing request message originating from the first peer nodevia the GTP link where the subsequent probing request message contains arequest indication for a probing interval recommendation for probing theGTP link. In these embodiments, in response to the subsequent probingrequest message received, the method further includes determining asubsequent probing interval recommendation for probing the GTP linkwhere the second probing interval recommendation is different from thecurrent probing interval. The method also includes sending a subsequentprobing response message to the first peer node via the GTP link wherethe subsequent probing response contains the subsequent probing intervalrecommendation. In yet other embodiments, the method further includesrepeating the acts of receiving, determining and sending for each of aplurality of probing request messages received from the first peer node.

In yet other embodiments, the probing interval recommendation is a firstprobing interval recommendation and the GTP link is a first GTP link,and the method further includes receiving a probing request messageoriginating from a second peer node via a second GTP link where theprobing request message from the second peer node contains a requestindication for a probing interval recommendation for probing the secondGTP link. In these embodiments, the method further includes in responseto the probing request received from the second peer node, determining asecond probing interval recommendation for probing the second GTP linkwhere the second probing interval recommendation is determinedindependently of the first probing interval recommendation. The methodfurther includes sending a probing response message to the second peernode via the second GTP link where the probing response message for thesecond peer node contains the second probing interval recommendation. Inyet other embodiments, the method further includes repeating the acts ofreceiving, determining and sending for probing the second GTP link withthe second peer node for each of a plurality of probing request messagesreceived from the second peer node.

In yet other embodiments, determining a probing interval recommendationfor probing the GTP link includes determining a probing intervalrecommendation based on at least one of a condition at the network nodeand a capability of the network node. In yet other embodiments,determining a probing interval recommendation for probing the GTP linkincludes determining a probing interval recommendation based on leastone of a capability of the network node, a congestion level at thenetwork node, a number of probe messages processed at the network node,a CPU utilization level at the network node, a traffic level for the GTPlink, a type for the GTP link, and a number of current GTP links at thenetwork node. In yet other embodiments, the GTP link comprises one of aGTP path, one or more GTP tunnels, one or more GTP-U tunnels and one ormore GTP-C tunnels.

In yet other embodiments, the probing request message includes a GTP-UEcho request and the probing response message includes a GTP-U Echoresponse and wherein the probing interval recommendation is included inone of an Information Element and a private extension of the GTP-U Echoresponse. In yet other embodiments, the probing request message includesa TWAMP Session-Sender test packet and the probing response messageincludes a TWAMP Session-Reflector test packet and wherein the probinginterval recommendation is included in a field of the TWAMPSession-Reflector packet.

In yet other embodiments, the request indication for a probing intervalrecommendation for probing the GTP link includes one of a flag, aprivate extension, a current probing interval value, a current probingmethod value, and a probing interval Information Element. In yet otherembodiments, the probing interval recommendation includes one of aprobing interval value and a probing method value indicative of aprobing interval value.

In another broad aspect, there is provided another method for a networknode for probing GTP links operable to carry data traffic between thenetwork node and peer nodes in a communication network. The methodincludes at the network node sending a probing request message to afirst peer node via a GTP link where the probing request messagecontains a request indication for a probing interval recommendation forprobing the GTP link. The method further includes receiving a probingresponse message from the first peer node via the GTP link where theprobing response message contains a probing interval recommendationdetermined by the first peer node.

In some implementations, the method further includes setting a probinginterval for the GTP link based on the probing interval recommendationdetermined by the first peer node. In other embodiments, the methodfurther includes setting a probing interval for the GTP link based onthe probing interval recommendation determined by the first peer nodeand at least one of a condition at the network node and a capability ofthe network node. In yet other embodiments, the method further includessetting a probing interval for the GTP link based on the probinginterval recommendation determined by the first peer node and at leastone of a capability of the network node, a congestion level at thenetwork node, a number of probe messages processed at the network node,a CPU utilization level at the network node, a traffic level for the GTPlink, a type for the GTP link, and a number of current GTP links at thenetwork node.

In some implementations, the method further includes sending asubsequent probing request message to the first peer node via the GTPlink at a time based on the probing interval set. In otherimplementations, the method further includes sending a subsequentprobing request message to the first peer node via the GTP link at atime based on the probing interval set, after receiving a number ofsuccessive probing response messages from the first peer node. In otherimplementations, the probing response message contains at least oneparameter associated with one of the probing request message, theprobing response message and the GTP link.

In yet other implementations, the probing interval recommendationcontained in the probing response message is a first probing intervalrecommendation and the method further includes sending a subsequentprobing request message to the first peer node via the GTP link wherethe subsequent probing request message contains a request indication fora probing interval recommendation for probing the GTP link. In thoseimplementations, the method further includes receiving a subsequentprobing response message from the first peer node via the GTP link wherethe subsequent probing response message contains a subsequent probinginterval recommendation determined by the first peer node and differentfrom the first probing interval recommendation. In yet otherimplementations, the method further includes repeating the acts ofsending a probing request message to the first peer node and receiving aprobing response message from the first peer node based on the probinginterval recommendation contained in the probing response message.

In yet other implementations, the probing interval recommendationcontained in the probing response message is a first probing intervalrecommendation and the GTP link is a first GTP link and the methodfurther includes sending a probing request message to a second peer nodevia a second GTP link wherein the probing request message to the secondpeer node contains a request indication for a probing intervalrecommendation for probing the second GTP link. The method furtherincludes receiving a probing response message from the second peer nodevia the second GTP link where the probing response message from thesecond peer node contains a second probing interval recommendationdetermined by the second peer node independently of the first probinginterval recommendation. In yet other implementations, the methodfurther includes repeating the acts of sending and receiving for probingthe second GTP link with the second peer node based on the secondprobing interval recommendation.

In yet other implementations, the probing interval recommendation isdetermined based on at least one of a capability of the first peer node,a congestion level at the first peer node, a number of probe messagesprocessed at the first peer node, a CPU utilization level at the firstpeer node, a traffic level for the GTP link, a type for the GTP link,and a number of current GTP links at the first peer node. In yet otherimplementations, the GTP link comprises one of a GTP path, one or moreGTP tunnels, one or more GTP-U tunnels and one or more GTP-C tunnels. Inyet other implementations, the probing request message includes a GTP-UEcho request and the probing response message includes a GTP-U Echoresponse and wherein the probing interval recommendation determined isincluded in one of an Information Element and a private extension of theGTP-U Echo response. In yet other implementations, the probing requestmessage includes a TWAMP Session-Sender test packet and the probingresponse message includes a TWAMP Session-Reflector test packet andwherein the probing interval recommendation determined is included in afield of the TWAMP Session-Reflector packet. In yet otherimplementations, the request indication for a probing intervalrecommendation for probing the GTP link includes one of a flag, aprivate extension, current probing interval value, a current probingmethod value, and a probing interval Information Element. In yet otherimplementations, the probing interval recommendation determined includesone of a probing interval value and a probing method value indicative ofa probing interval value.

In another broad aspect, there is provided a network node configured toprobe GTP links operable to carry data traffic between the network nodeand peer nodes in a communication network, where the network nodeincludes circuitry containing instructions which, when executed, causethe network node to perform any of the method embodiments describedabove. In some embodiments, the network node includes a radio accessnode (e.g. an eNodeB or Wireless Local Access Network (WLAN AccessPoint), an S-GW node or MBMS-GW node.

In yet another broad aspect, there is provided a non-transitory computerreadable memory configured to store executable instructions for anetwork node and where the network node is configured to probe GTP linksoperable to carry data traffic between the network node and peer nodesin a communication network, and where the executable instructions whenexecuted by a processor cause the network node to implement any of theabove method embodiments described above.

In yet another broad aspect, there is provided a network node configuredto probe GTP links operable to carry data traffic between the networknode and peer nodes in a communication network, where the network nodeincludes a receiver for receiving a probing request message originatingfrom a first peer node via a GTP link where the probing request messagecontains a request indication for a probing interval recommendation forprobing the GTP link. The network node also includes an intervalrecommendation determining module for determining a probing intervalrecommendation for probing the GTP link in response to the probingrequest message received. The network node also includes a transmitterfor sending a probing response message to the first peer node via theGTP link where the probing response message contains the probinginterval recommendation determined.

In yet another broad aspect, there is provided a network node configuredto probe GTP links operable to carry data traffic between the networknode and peer nodes in a communication network, where the network nodeincludes a transmitter for sending a probing request message to a firstpeer node via a GTP link, where the probing request message contains arequest indication for a probing interval recommendation for probing theGTP link. The network node also includes a receiver for receiving aprobing response message from the first peer node via the GTP link,where the probing response message contains the probing intervalrecommendation determined by the first peer node. In someimplementations, the network node also includes an interval settingmodule for setting a current probing interval based on the probinginterval recommendation determined by the first peer node.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete understanding of the present disclosure, and theattendant advantages and features thereof, will be more readilyunderstood by reference to the following detailed description whenconsidered in conjunction with the accompanying drawings in which likereference designators refer to like elements and wherein:

FIG. 1 illustrates an example of a Long Term Evolution (LTE) network inwhich nodes are configured to probe General Packet Radio System (GPRS)Tunneling Protocol (GTP) links using probing request and responsemessages, in accordance with the principles described herein;

FIG. 2 illustrates an example of another LTE network in which nodes areconfigured to probe GTP links using probing request and responsemessages, in accordance with the principles described herein;

FIG. 3 is a signaling diagram example of a method for probing a GTP linkin the LTE network of FIG. 1 or 2 established between a GTP-U echooriginator and GTP-U echo responder, in accordance with the principlesdescribed herein;

FIG. 4 is an example of an extension for the echo request and responsemessages of FIG. 3, in accordance with the principles described herein;

FIG. 5 is a flow chart example of a method for a responder network nodefor probing a GTP link with a peer node in the LTE network of FIG. 1 or2, in accordance with the principles described herein;

FIG. 6 is a flow chart example of another method for a responder networknode for probing a GTP link with a peer node in the LTE network of FIG.1 or 2, in accordance with the principles described herein;

FIG. 7 is a flow chart example of a method for an originator networknode for probing a GTP link with a peer node in the LTE network of FIG.1 or 2, in accordance with the principles described herein;

FIG. 8A-8B shows a block diagram of exemplary embodiments of networknodes configured as originator and responder in accordance withprinciples of the present disclosure; and

FIG. 9A-9B shows a block diagram of other exemplary embodiments ofnetwork nodes configured as originator and responder in accordance withprinciples of the present disclosure.

DETAILED DESCRIPTION

Before describing in detail exemplary embodiments, it is noted that theembodiments reside primarily in combinations of apparatus components andprocessing steps related to the probing of links in a communicationnetwork.

Accordingly, the system and method components have been representedwhere appropriate by conventional symbols in the drawings, showing onlythose specific details that are pertinent to understanding theembodiments of the present invention so as not to obscure the disclosurewith details that will be readily apparent to those of ordinary skill inthe art having the benefit of the description herein.

As used herein, relational terms, such as “first” and “second,” “top”and “bottom,” and the like, may be used solely to distinguish one entityor element from another entity or element without necessarily requiringor implying any physical or logical relationship or order between suchentities or elements.

Embodiments described herein illustrate probing methods and systems toenable the collection of end-to-end performance information for GeneralPacket Radio System (GPRS) Tunneling Protocol (GTP) links established ina communication network for administrative, troubleshooting,quality-of-service (QoS) monitoring, user traffic profiling, planning,Internet Protocol (IP) bandwidth on demand, and radio feature activationpurposes. As such, the following description generally applies to theprobing of GTP links between an originator node (or endpoint) and aresponder node (or endpoint). In some implementations, a GTP linkincludes one or more (e.g. a set of) GTP tunnels. In otherimplementations, a GTP link includes a path (e.g. a connection-lessunidirectional or bidirectional path used to multiplex GTP tunnels anddefined by two endpoints (e.g. themselves each defined by an IP addressand a UDP port number). Depending on whether any GTP tunnel has beenestablished, it is possible that a GTP path may or may not have any GTPtunnels associated therewith at any given time. Examples of GTP linksinclude GTP-U tunnels and paths for user data traffic as well as GTP-Ctunnels and paths for signaling traffic. In yet other implementations, aGTP link may be a unicast or multicast path or tunnel. Generallyhowever, it is to be understood that the principles described thereinalso apply to the probing of any link capable or configured to useprobing request/response messages as described herein. For clarity, thefollowing examples are in relation to the probing of GTP links.

In addition, the examples and embodiments provided below describe hownodes or endpoints in a cellular or radio communication network such asa Long Term Evolution (LTE) network can be configured for link probing.However, those having ordinary skill in the relevant art will readilyappreciate that the principles described herein may equally apply toother types of networks. For example, the radio communication networkmay also include other 3^(rd) Generation Partnership Project (3GPP)networks (e.g. Universal Mobile Telecommunications System UMTS,LTE-Advanced (LTE-A)), LTE-Unlicensed (LTE-U), 4^(th) Generation (4G),5^(th) Generation (5G) or other future generations of a 3GPPcommunication network infrastructure as well as other types of wirelesscommunication networks such as Wireless Local Access Networks (WLANs).More generally, the radio communication network may include any currentor future wireless access and core network infrastructure with nodesand/or endpoints adapted to or configured for probing GTP links using aprobing request/response mechanism.

Referring now to FIG. 1, there is shown an example of a LTE network 10in which access nodes 16, 18, 20 and Core Network (CN) nodes 12, 14 areconfigured to probe links 22, 26, 28, 30, 32, 34 using a dynamic oradaptive probing request/response mechanism 50A-G configured inaccordance with principles described herein (further details below).Generally, the LTE network 10 may include additional and/or differentaccess and/or Core Network (CN) nodes connected via GTP links but forclarity, the LTE network in the example of FIG. 1 is shown to includeonly three access nodes (i.e. evolved NodeB (eNB)) 16, 18, 20 and two CNnodes which in this case are a Serving Gateway (S-GW) 12 and a Mobilitymanagement Entity (MME) 14. However, it is understood that other networkconfigurations for the LTE network 10 are possible includingconfigurations with MBMS SW and/or WLAN (e.g. Wi-Fi) nodes or AccessPoints (APs).

In the LTE network 10 of FIG. 1, the eNBs 16, 18, 20 and the S-GW 12 areinterconnected with GTP-U links 50B-G while the MME 14 is connected witheach eNB 16, 18, 20 via IP-based link 22 (only one connection shown).Data traffic between the eNBs 16, 18, 20 is sent over GTP-U links 30,32, 34 while traffic between each eNB 16, 18, 20 and the S-GW 12 is sentover the S1-U interface also via GTP-U links 24, 26, 28. Link 22 carriesS1-AP signalling messages between the eNBs 16, 18, 20 and the MME 14.Each access nodes 16, 18, 20 is an eNB but in other implementations, theaccess nodes 16, 18, 20 may each be a Node B (NB), base station, basestation controller (BSC), radio network controller (RNC), relay, donornode controlling relay, base transceiver station (BTS), transmissionpoint, transmission node, remote RF unit (RRU), remote radio head (RRH),a node in a distributed antenna system (DAS), or a memory managementunit (MMU). Generally, the access node 16, 18, 20 is configured to probelinks 22, 24, 26, 28, 30, 32, 34 with peer nodes or endpoints but othernodes in the LTE network RAN 10 or in a network outside of the RAN/CNinfrastructure (e.g. an Internet Protocol (IP) node in an IP network)may be configured for that purpose. It is to be understood that thefunctionality described herein in relation probing GTP links may alsoequally apply to any node or endpoint terminating a link as shown and/ordescribed.

According to principles described herein, each of the nodes 12, 14, 16,18, 20 in the LTE network of FIG. 1 is configured to probe the links itterminates with a probing request/response mechanism 50A-G that uses adynamic probing interval (further details below). Depending on theimplementation, the nodes 12, 14, 16, 18, 20 are each configured eitheras an originator (to send probing requests), as a responder (to respondto probing requests) or as both.

Referring now to FIG. 2, there is shown an example of another LTEnetwork 100 in which nodes and endpoints are configured to probe linkswith a dynamic probing request/response mechanism 150A-N in accordancewith principles described herein. Specifically, the LTE network 100includes a number of eNBs 112, 114, 116, 118, 120, 122 and core networkfunctionality (e.g. MBMS-GW, S-GW and/or MME functionality) implementedin cloud computing infrastructure 110 which itself may include one ormore servers, nodes, blades, I/O interfaces and/or processing or controlcircuitry configured to implement such functionality in the same ormultiple different locations. The eNBs 112, 114, 116 are configured tointeract with such core network functionality via links 130A-C toendpoints 160, 164, 168 and GTP links 132A-C to endpoints 162, 164, 170.In the example of FIG. 2, endpoints 160, 164 and 168 are configured toprovide MME functionality while endpoints 162, 166, 170 implement S-GWfunctionality.

In the example of FIG. 2, eNB 112 is configured with a split layerarchitecture where some of the layer functionality, for example PDPCpacket processing, is performed by one central eNB node or unit 112(e.g. a Packet Data Convergence Protocol (PDCP) Packet Unit (PPU)) andother layer functionality for example Media Access Control(MAC)/Physical (PHY) processing, is located in one or more Baseband Unit(BBU) eNBs 118, 120, 122 serving different cells. In the example of FIG.2, the PPU eNB 112 is configured with (internal) GTP links 142A-C to itsassociated BBU eNBs 118, 120, 122 and with (external) GTP links 140A-Cto interconnect with other eNBs 114, 116 which may or may not have asplit architecture. The BBU eNBs 118, 120, 122 are interconnected withone or more GTP links 142D, 142E. Data traffic between eNBs 112, 114,116, 118, 120, 122 is sent over GTP-U links 140A-C, 142A-E via the X2-Uinterface while traffic between each eNB 112, 114, 116 and a respectiveS-GW endpoint 162, 166, 170 is sent over the S1-U interface via GTP-Ulinks 132A-C. Links 160, 164, 168 carry S1-AP signalling messagesbetween the eNBs 112, 114, 116 and a respective MME endpoint 160, 164,168.

In accordance with principles described herein, each of the eNBs 112,114, 116, 118, 120, 122 and endpoints 160, 162, 164, 166, 168, 170 inthe LTE network of FIG. 2 is configured to probe links it terminateswith a probing request/response mechanism 150A-150M that uses a dynamicprobing interval (further details below). Depending on theimplementation, the eNBs 112, 114, 116, 118, 120, 122 and endpoints 160,162, 164, 166, 168, 170 are each configured either as an originator, asa responder or as both.

As will be explained below in greater detail, in some implementations,the probing interval in at any of the nodes or endpoints shown in theLTE networks 10, 100 of FIGS. 1, 2 can be changed dynamically to adaptthe probing frequency to the prevailing conditions measured and/orcapabilities available at either the originator node/endpoint or theresponder node/endpoint. A dynamic probing interval may be useful inimplementations where, for example, either the originator or theresponder is subject to performance variations (e.g. throughput, load)either at the link level or at the node level. By dynamically adjustingthe probing interval, it may be possible for nodes/endpoints to adapttheir ability to probe based on current conditions and/or capabilitiesand hence optimize the probing such that interference with each node'sperformance is reduced or minimized.

In other implementations, the probing interval for a given link can bechanged independently of probing interval used for other links.Referring back to the LTE network 10 of FIG. 1 for example, the eNB 16might select a probing interval for GTP link 24 independently from theprobing interval it might use for probing GTP links 30, 32. In yet otherimplementations, the probing interval is selected based on currentconditions and/or capabilities of the responder. For example, ifconfigured as originator, the eNB 16 might select a probing interval forprobing GTP link 32 which is based on current conditions measured and/orcapabilities available of eNB 18 while the probing interval for probingGTP link 24 is selected based current conditions and/or capabilities ofthe S-GW 12. This may generally be advantageous, in implementationswhere different responder nodes operate under different conditionsand/or have capabilities which are different from those of theoriginator node. For example, in a network configured for inter-eNBcarrier aggregation, the different types of eNBs used (e.g. macro/picoeNBs) might operate under different conditions and/or have differentcapabilities. In these implementations, an eNB configured as anoriginator node can advantageously tailor the probing of links withdifferent responder nodes based on their respective ability to respondto probe requests.

Turning now to FIG. 3, there is shown a signaling diagram example 200 ofa method for probing a GTP-U link between a GTP-U originator 210 and aGTP-U responder 220 which may be any node or endpoint configured toterminate a GTP-U link such as those shown in FIG. 1 or 2. In thisexample, the originator 210 is configured to probe the GTP-U link usingGTP-U echo request messages 222A-C (only three shown) which it sendsperiodically to the responder 220. If the responder 220 receives an echorequest message 222A-C, it sends a GTP-U response message 224A-C back tothe originator 210 confirming it is active and reachable. GTP-U echorequest and response messages 222A-C, 224A-C are examples of the probingrequest/response mechanisms described in relation to FIGS. 1 and 2.However, in other implementations, other types of GTP messages or otherprobing request/response messages could be used. For example, inimplementations where the GTP-U link probed is a multicast link, theprobing request message is a multicast probing request (e.g. a multicastecho request) sent to a plurality of responders 220 and the probingresponse message sent by each responder 220 is a unicast echo responsemessage (e.g. a unicast echo response). In another example, the probingrequest message could be a Two-Way Active Measurement Protocol (TWAMP)Session-Sender test packet and the probing response message could be aTWAMP Session-Reflector test packet. Other possibilities exist for theprobing request/response messages.

The GTP-U echo request 222A-C includes GTP, UDP and IP headers 226B-Dwhile the GTP-U echo response includes a recovery field 228B as well asGTP, UDP and IP headers 228C-E. Based on measurement(s) contained in theecho requests 222A-C sent and responses 224A-C received, the originator210 can determine (or have determined at a different node) performancemetrics or Key Performance Indicators (KPIs) associated with the GTPlink probed. Metric examples includes one-way (forward or reverse) ortwo-way delay metrics, packet delay variation metrics, packet lossmetrics, misordering metrics, packet QoS marking metrics,originator/responder bitrate metrics, etc. In some embodiments, thesemetrics can be expressed in the form of a path or tunnel performancereport. Other possibilities exit for producing one or more metrics basedon the echo requests 222A-C and responses 224A-C.

According to principles of the present disclosure, the originator 210 isconfigured to send echo requests 222A-C using an adaptive probinginterval (i.e. the time duration between two successive echo requests222A-C). Depending on the conditions and/or capabilities currentlyprevailing at the responder 220, the originator 210 can change theprobing interval dynamically so as to optimize the probing (e.g. withoutnegatively impacting each node's performance). In the example of FIG. 3,the originator is configured to set the probing interval to a value of1, 5 or 60 seconds. However, it is understood that different oradditional interval values could be used. In some implementations, theprobing interval is increased when a current performance conditionand/or capability of the responder (e.g. a load) is greater than apredetermined performance value (e.g. set in a policy). In otherimplementations, the probing interval is decreased when the responderperformance condition and/or capability is lower than the predeterminedvalue. In yet other implementations, the probing interval is maintainedwhen the current performance condition and/or capability is equal to ormeets the predetermined performance value. In yet other implementations,the probing interval is gradually increased or decreased based whetherthe current performance condition and/or capability increases ordecreases relative to a predetermined performance value. Generally, theprobing interval is set such that the probing frequency can be adapteddynamically based on current conditions measured and/or capabilitiesavailable at either the originator or responder (further details below).

According to principles of the present disclosure, the originator 210determines the appropriate probing interval based on a probing intervalrecommended by the responder 220 for probing the GTP-U link. In someimplementations, the originator 210 includes a request indication for aprobing interval recommendation in one or more echo request messages222A-C. If an echo request message 222A-C contains a request for aprobing interval recommendation, the responder 220 includes arecommended probing interval value in its echo response 224A-C. Inimplementations where the GTP-U link is a multicast link and the echorequest message 222A-C is a multicast echo request, each responder 220includes a recommended probing interval value in its unicast echoresponse 224A-C. Based on the value(s) recommended for probing the GTP-Ulink, the originator 210 sets its current probing interval to a newvalue which, in some cases, may be greater, lower or equal to theprobing interval value currently used by the originator 210.

In some implementations, the request indication is a current probinginterval value or another value indicative of a current probing intervalvalue such as, for example, a probing method value, an InformationElement (IE) value, a flag value or an index value. Other possibilitiesexist for request indication. In some implementations, the requestindication for a probing interval recommendation is included in anextension 226A of the echo request message 222A-C. In otherimplementations, the request indication may be included as a flag, anindex, an IE, or another field of the echo request message 222A-C.

In some embodiments, when the responder 220 receives an echo request222A-C containing a request indication for a probing intervalrecommendation, the responder 220 is configured to determine a suitableprobing interval or method (e.g. based on its current conditions and/orcapabilities), and send a corresponding probing interval recommendationin an echo response 224A-C. In some implementations, the probinginterval recommendation is a probing interval value, or another valueindicative of a particular probing interval value such as, for example,a probing method value, an Information Element (IE) value, a flag valueor an index value. Other possibilities exist for probing intervalrecommendation. In some implementations, the probing intervalrecommendation is included in an extension 228A of the echo responsemessage 224A-C. In other implementations, the probing intervalrecommendation may be included as a flag, an index, an InformationElement or as another field of the echo response message 224A-C. In yetother implementations, the extension 228A and the extension 226A is thesame IE and the probing interval recommendation is included is the samefield in the IE used for the request indication.

FIG. 4 is an example of an extension 300 for the echo request andresponse messages of FIG. 3 in accordance with principles describedherein. In this example, the extension 300 is an IE that includes asampling interval field 316 that can be used by the originator 210 inits echo request message(s) 222A-C to specify a request indication for aprobing interval recommendation. The sampling interval field 316 canalso be used by the responder 220 in its echo response message(s) 224A-Cto specify a probing interval recommendation. In some implementations,the values specified in Table A below are used by the originator 210 todenote a current sampling interval or method and by the responder 220 todenote a recommended or preferred sampling interval/method.

TABLE A Value Meaning 0 Slow periodic transmission (1 echo request perminute) 1 Fast periodic transmission (1 echo request per second) 2-255Reserved

In the echo request message 222A-C, the originator 210 uses the samplinginterval field 316 both as a request indication to the responder 220 fora probing interval recommendation and as a way to indicate a probinginterval recommendation method or value. For example, the originator 210sets the sampling interval field 316 to a value of 0 to indicate to theresponder 220 that the probing method it currently uses is one echorequest per minute (60 second interval). The originator 210 can also setthe sampling interval field to a value of 1 to indicate that the probingmethod it currently uses is one echo request per second (one secondinterval). In other implementations, different or additional valuescould be used for the request indication and/or to provide more or lesspossibilities for the different probing interval methods or valuessupported by the originator 210.

In the echo response message 224A-C, the responder 220 uses the samplinginterval field 316 as a way to indicate a preferred or recommendedprobing interval method or value. For example, the responder 220 setsthe sampling interval field 316 to a value of zero to indicate to theoriginator 210 that its preferred probing method is one echo request perminute (60 second interval). The responder 220 can also set the samplinginterval field 316 to a value of one to indicate that the probing methodit prefers is one echo request per second (one second interval). Inother implementations, the responder 220 sets the sampling intervalfield 316 to a default method value (e.g. one). In otherimplementations, different or additional values could be used to providemore or less possibilities for the different probing interval methods orvalues supported by the responder 220.

In the example of FIG. 4, the extension 300 also contains type andlength fields 310, 312 as well as an extension identifier field whichcan be used to assist the responder 220 in determining whether it can orshould read the extension 300 and respond appropriately. In other words,if the extension is not supported by responder 220, the extension 300 isignored and the rest of the echo request message 222A-C is processedconventionally. According to principles of the present disclosure, theextension 300 also has a number of fields 318-330 that the originator210 and/or responder 220 can use to include measurements and/orparameters associated with the echo request message 222A-C, the echoresponse message 224A-C and/or associated with the probed GTP-U linkitself. In the specific example of FIG. 4, the extension 300 contains arequest exit timestamp field 318 used by the originator 210 forspecifying an exit time for the echo request message, a request arrivaltimestamp field 320 used by the responder 220 for specifying an arrivaltime for the echo request message, a response exit timestamp field 322used by the responder 220 for specifying an exit time for the echoresponse message.

The extension 300 also contains a request Differentiated Service CodePoint (DSCP) field 324 and a Travel Length (TTL) field 326 used by theresponder 220 used for specifying the DSCP and IPv4 or IPv6 hop countdetected for the associated echo request message received. The extension300 also contains a responder sequence number field 328 used by theresponder 220 for specifying the sequence number of the echo responsesaccording to their transmit order. In some implementations, the sequencestarts at zero and is incremented by one by the responder 220 for eachecho response message sent. In other implementations, the sequencenumber set by the responder 220 is generated independently from thesequence number associated with incoming echo request messages and setby the originator 210. Finally, the extension 330 contains a responderidentifier field 330 that can be used by the responder to identifyitself as the responder in the echo response message 224A-C.

It is important to note that the originator 210 and/or responder 220 maydecide to use only a subset of the extension fields described above. Forexample, in some implementations, the extension fields set by theoriginator 210 are not included in the extension 300 contained in theecho request message(s) 222A-C. Similarly, in other implementations, theextension fields set by the responder 220 are not included in theextension 300 contained in the echo response message(s) 224A-C. Otherpossibilities exist for the extension 300 used by the originator 210 andresponder 220.

It is also possible that in other implementations, new echo request andresponse messages which are different from conventional echo messages(e.g. identified by a different message type value) can be used tocontain the originator request indication for a probing intervalrecommendation, the responder probing interval recommendation and/or anyof the other extension fields populated by the originator 210 and/orresponder 220 and described above in relation to FIG. 4.

Turning now to FIG. 5, there is shown a flow chart example of a method400 for a network node for probing GTP links operable to carry datatraffic between the network node and a peer node in the LTE network ofFIG. 1 or 2, in accordance with the principles described herein. In thisexample, the network node is configured as a responder and the peer nodeis configured as an originator. The method 400 begins at step S402 wherethe network node (the responder) receives a probing request message fromthe peer node (the originator) via a GTP link where the probing requestmessage contains a request indication for a probing intervalrecommendation for probing the GTP link. In response to the probingrequest message received, the responder network node determines at stepS404 a probing interval recommendation for probing the GPT link. At stepS406, the responder network node sends via the GTP link a probingresponse message to the originator peer node containing the probinginterval recommendation determined at which point the method returns tostep S402 when it receives another probing request message.

In some implementations, the method repeats itself every time a newprobing request message is received from the originator peer node. Inthose implementations, the probing interval for probing the GTP link canbe changed dynamically every time a new probing request message isreceived from the originator peer node to adapt the probing frequency tothe prevailing conditions measured and/or capabilities available at theresponder network node. In other implementations, the probing intervalrecommendation determination at step S404 is performed only for everyN^(th) probing request received. Other possibilities exit fordynamically adjusting the probing interval. A dynamic probing intervalmay be useful in implementations where, for example, the respondernetwork node is subject to performance variations over time, either atthe link level or at the node level. Also, by providing a mechanism toallow the responder network node to change its recommended probinginterval dynamically, it may be possible for the responder network nodeto continuously take into consideration its current conditions and/orcapabilities as the probing is performed and hence optimize the probingdone such that it does not interfere with the responder network node'sperformance.

FIG. 6 is a flow chart example of another method 500 for a network nodeconfigured for probing a GTP link with a peer node in a communicationnetwork (e.g. the LTE network of FIG. 1 or 2), in accordance with theprinciples described herein. In this example, the network node isconfigured as a responder and the peer node is configured as anoriginator. The method 500 begins at step S502 where the respondernetwork node receives a probing request message (e.g. an echo/proberequest) from the originator peer node for probing the GTP link. At stepS504, the responder network node determines if the probe requestcontains a request for a probing interval recommendation. If a probinginterval recommendation request not included, the responder network nodeproceeds to step S508 where it sends a probing response message (e.g. anecho/probe response) to the originator peer node that containsmeasurements and/or parameters associated with the probe request, theprobe response and/or associated with the probed GTP link itself. If,alternatively, a probing interval recommendation request is included inthe probe request, the responder network node determines at step S506 ifthe probe request received is the N^(th) probe request (or the N^(th)probe request with a probing interval request) received. The value of Nmay be selected based on how responsive the implementation needs to be.For example a large value of N may be useful in implementations where itis desirable to reduce and/or minimize changes to the probing interval.Alternatively, a small N may be useful in implementations where it isdesirable to keep maintain close alignment between the probing and theconditions and/or capabilities prevailing at the responder network node.Example values for N include 1, 5, 10, 50, 100 but other possibilitiesexist for N.

If the probe request received is the N^(th) probe request (or the N^(th)probe request with a probing interval recommendation request) received,the responder network node evaluates (e.g. determines) at step S510 oneor more of its conditions and/or capabilities currently prevailingeither for the GTP link being probed and/or for the responder networknode generally. Examples of current conditions and/or capabilitiesincludes a congestion level, a number of probe requests previouslyprocessed or discarded, a CPU utilization level, a traffic level for theGTP link, a number of active or current GTP links, a type for the GTPlink, etc.

At step S512, the responder network node selects a probing intervalrecommendation based on the current responder conditions and/orcapabilities determined. In some implementations, the responder networknode compares the condition(s) and/or capability (ies) evaluated againsta defined value, threshold or range which, in some cases, may bepreconfigured, predetermined or defined in a policy or configurationfile. In one example, when the responder condition(s) and/orcapability(ies) determined (e.g. a load associated with the GTP link ornetwork node) is greater than a policy value, the responder network nodeselects a large interval which if adopted by the originator, wouldresult in slower probing. When the current condition(s) and/orcapability(ies) determined meets the policy value, the responder networknode continues to select the same interval recommendation i.e. same as apreviously selected interval recommendation). When the condition(s)and/or capability(ies) determined is lower than the policy value, theresponder network node selects a small interval which, if adopted by theoriginator, would result in faster probing.

However, depending on the type of condition(s) and/or capabilities usedfor its probing interval recommendation, the responder network node maybehave differently. For example, if the condition and/or capability isthe throughput associated with the GTP link or network node, instead ofselecting a large interval when the current throughput determined isgreater than a policy value, the responder network node may do theopposite i.e. select a small interval to speed up the probing.Similarly, instead of selecting a small interval when the currentthroughput determined is lower than a policy value, the respondernetwork node may select a large interval to slow down the probing. Also,instead of selecting the same interval when the current throughputdetermined meet the policy value, the responder network node may selecta larger or smaller interval, for example, progressively over severalprobe requests, to optimize the probing until or unless the currentthroughput deteriorate beyond the policy value. Other implementationsfor the responder network node to select its recommended interval arepossible.

At step S518, the responder network node sends via the GTP link aprobing response (e.g. an echo/probe response) to the originator peernode containing the selected probing interval recommendation as well asmeasurements and/or parameters associated with the probe request, theprobe response and/or associated with the probed GTP link itself. After,the method 500 returns to step S502 to handle the next probe request.

Similarly to the method 400 of FIG. 5, in some implementations, adynamic probing interval may be useful in implementations where, forexample, the responder network node is subject to performance variationsover time, either at the link level or at the node level. Also, byproviding a mechanism to allow the responder network node to change itsrecommended probing interval dynamically, it may be possible for theresponder network node to continuously take into consideration itscurrent conditions and/or capabilities as probing requests are receivedand hence optimize the probing done such that it does not interfere withthe responder network node's performance.

In some implementations, the probing interval recommendation for a givenlink can be changed independently of probing interval used for otherlinks. In those implementations, each of the methods described above inrelation to FIG. 5 or 6 can be performed by the responder network nodeindependently of any probing that might be done for other GTP links withthe originator peer node or other originator peer nodes. For example, ifalso configured as responder for another GTP link terminated at anotheroriginator peer node, the network node might determine a probinginterval recommendation for that other GTP link that might be differentthan the probing interval recommendation determined for the GTP linkwith the first originator peer node. Alternatively, if configured as anoriginator for that other GTP link, the network node might use a probinginterval recommendation determined by the other peer node (configured asa responder node) which is different from the probing intervalrecommendation it determined as a responder for the first GTP link.Generally, in these implementations, the probing is link specific. Inother words, for any given GTP link, the responder node determines itsrecommended probing interval and the originator node sets the finalprobing interval independently of any other GTP link they mightterminate (either as originator or responder). With that approach, anoriginator node can advantageously tailor the probing of different GTPlinks based on, for example, the respective ability of the respondernode to respond to probe requests and/or the type of GTP link (includingthe type of underlying interface over which the GTP link is established(e.g. S1-U, X2-U between eNBs or X2-U between a PPU eNB and a BBU eNB,or the M1 link between MBMS-GW and eNBs)).

FIG. 7 is a flow chart example of yet another method 600 for a networknode for probing GTP links operable to carry data traffic between thenetwork node and a peer node in the LTE network of FIG. 1 or 2, inaccordance with the principles described herein. In this example, thenetwork node is configured as an originator and the peer node isconfigured as a responder. The method 600 begins at step S602 where theoriginator network node sends a probing request message (e.g. anecho/probe request) to the responder peer node via a GTP link where theprobing request message contains a request indication for a probinginterval recommendation for probing the GTP link. The probing requestmessage is sent at a time based on a current probing interval set by theoriginator network node. In response to the probing request messagesent, the originator network node receives from the responder peer nodevia the GTP link a probing response message at step S604 that contains aprobing interval recommendation determined by the responder peer nodefor probing the GPT link as well as measurements and/or parametersassociated with the probing request message, the probing responsemessage and/or associated with the probed GTP link itself. In someimplementations, the originator network node may optionally wait toreceive the same responder probing interval recommendation a number oftimes before setting a new value for the current probing interval (atstep S610). In those implementations, the originator network node maydetermine at step S606 whether a (predetermined or configured) number Kof successive probing response messages with the same responder probinginterval recommendation has been received. Example values for K include1, 3 and 5 but other values are possible. If the originator network nodedetermines that the number K of successive probing responses has notbeen reached, the originator network node maintains the same value forits current probing interval and the method 600 returns to step S602 tosend the next probing request at a time based on the unchanged (current)interval value.

If, on the other hand, the originator network node determines that a(predetermined or configured) number K of successive probing responsemessages with the same responder probing interval recommendation hasbeen received, the originator network node then evaluates (e.g.determines) at step S608 one or more of its conditions and/orcapabilities currently prevailing for the GTP link being probed and/orfor the originator network node generally. Examples of currentoriginator conditions and/or capabilities includes a congestion level, anumber of probe requests transmitted per second, a CPU utilizationlevel, a traffic level for the GTP link, the type of GTP link/underlyinginterface over which the GTP link is established (e.g. S1-U, X2-Ubetween eNBs or X2-U between a PPU eNB and a BBU eNB or M1 betweenMBMS-GW and eNBs), a number of active or current GTP links, etc.

At step S610, the originator network node sets the current probinginterval for the GTP link based on the responder probing intervalrecommendation and the originator's current condition(s) and/orcapability(ies) and the method returns to step S602 to send the nextprobing request at a time based on the current interval set. In someimplementations, the originator network node sets the current probinginterval at step S610 to a value greater or equal to the responderprobing interval recommendation, based on its current originatorcondition(s) and/or capability(ies). In other implementations, theoriginator network nodes sets the current probing interval to be thelargest of the responder probing interval recommendation and a probinginterval value the originator can handle based on the its currentcondition(s) and/or capability(ies). Advantageously in thoseimplementations, the current probing interval can be set dynamicallysuch that the probing for any given link can be handled by both theoriginator and responder, including the one with the weaker performanceor under the more difficult constraints. Other methods for setting thecurrent probing interval at the originator network node are possible.

In some implementations, a counter k can be used to track the number ofsuccessive probing responses received with the same probing intervalrecommendation. In those implementations, the counter is incremented byone (e.g. in step S604) after each probing response received with thesame probing interval recommendation value) and is reset to a value ofzero after the number K of successive probing responses received withthe same probing interval recommendation value has been reached (e.g.yes branch of step S606 or in S608) or when a new probing intervalrecommendation value has been received before K successive probingresponses were received with the same probing interval recommendationvalue. Other possibilities exist for keeping track of the number ofsuccessive probing responses received with the same probing intervalrecommendation. In other implementations, the method repeats itself forevery new probing request message sent to the responder peer node. Inthose implementations, the probing interval can be changed dynamicallyevery time K successive probing response messages containing the samenew probing interval recommendation value are received from theresponder peer node. As noted above, in some implementations, theprobing interval recommendation value received may be based on currentconditions and/or capabilities available at the responder peer node.

In some implementations, additional or different steps to those shown inFIG. 7 may be performed by the originator network node. In oneimplementation, the originator network node performs the method 600after it has determined the responder peer node is reachable oravailable, for example, by determining that at least a predeterminednumber (e.g. three) of probing responses has been received and/or theresponder peer node status has changed from unreachable to reachable. Inanother implementation, the originator network node sets a default orinitial value for its current probing interval before it performs themethod 600. In yet another implementation, at step S608, the originatornetwork node sets its current interval value based on the probinginterval value recommended by the responder peer node but also its owncurrent condition(s) and/or capability(ies). In yet anotherimplementation, the originator network node sets its current interval tothe largest of the probing interval recommendation received from thepeer node and the probing interval that the originator network nodeitself can handle based on its own condition(s) and/or capability(ies).In yet another implementation, the originator network node makes thefinal determination of what the current probing interval should be forsubsequent probing requests.

In some implementations, the probing interval used by the originatornetwork node for a given link can be changed independently of probingintervals used for other links. In those implementations, the method 600described above in relation to FIG. 7 can be performed by the originatornetwork node independently of any probing that might be done for otherGTP links with the responder peer node or other responder peer nodes.For example, if also configured as an originator for another GTP linkterminated at another responder peer node, the originator network nodemight set a probing interval for that other GTP link that might bedifferent than the probing interval set for the GTP link with the firstresponder peer node as the recommended probing intervals from theresponder peer nodes might be different. Alternatively, if configured asa responder for that other GTP link, the network node might insteadprovide a probing interval recommendation to the other peer node(configured as an originator) that is different than the one it mightuse for the first GTP link. Generally, in these implementations, theprobing is link specific and with that approach, an originator node canadvantageously tailor the probing of different GTP links based on, forexample, the respective ability of the responder node to respond toprobe requests, the type of GTP link/underlying interface over which theGTP link is established (e.g. S1-U, X2-U between eNBs or X2-U between aPPU eNB and a BBU eNB or M1 between MBMS-GW and eNBs).

FIGS. 8A-B are block diagrams of exemplary embodiments of network nodes1000, 1100 configured respectively as originator and responder nodes(e.g. such as those described in relation to FIGS. 1-7 above) forprobing GTP links with peer nodes in accordance with the principles ofthe present disclosure.

As illustrated in FIG. 8A, originator network node 1000 includes atransceiver 1002, one or more processor(s) 1004, and memory 1006 whichincludes an interval setting module 1008. In one embodiment, thetransceiver 1002 may be replaced by a transmitter and a receiver (notshown). The transceiver 1002 is configured to perform the sending andreceiving functionality described above for an originator node which, asnoted above includes sending to a peer node via a GTP link a probingrequest message containing a request indication for a probing intervalrecommendation for probing the GTP link and receiving from the peer nodea probing response message containing a probing interval recommendationdetermined by the peer node. The interval setting module 1008 isconfigured to perform the interval setting functionality described abovein relation to an originator node, which includes setting a currentprobing interval based on the probing interval recommendation determinedby the peer node.

The interval setting module 1008 is implemented at least partially inthe memory 1006 in the form of software or (computer-implemented)instructions executed by the processor(s) 1004 within the originatornetwork node 1000 or distributed across two or more nodes (e.g., theoriginator network node 1000 and another node). In another example, thesending and receiving functionality described above in relation to anoriginator node is instead implemented in the form of software or(computer-implemented) instructions executed by the processor(s) 1004 incombination with the transceiver 1002 within the originator network node1000 or distributed across two or more nodes (e.g., the network node1000 and another node). In yet another example, the processor(s) 1004includes one or more hardware components (e.g., Application SpecificIntegrated Circuits (ASICs)) that provide some or all of the sending,receiving and interval setting functionality described above. In anotherembodiment, the processor(s) 1004 include one or more hardwarecomponents (e.g., Central Processing Units (CPUs)), and some or all ofthe sending, receiving and/or interval setting functionality describedabove is implemented in software stored in, e.g., the memory 1006 andexecuted by the processor 1004 in combination with the transceiver 1002.In yet another embodiment, the processor(s) 1004 and memory 1006 formprocessing means (not shown) configured to perform the sending,receiving and/or interval setting functionality described above.

As illustrated in FIG. 9B, responder network node 1100 includes atransceiver 1102, one or more processor(s) 1104, and memory 1106 whichincludes an interval determining module 1108. In one embodiment, thetransceiver 1102 may be replaced by a transmitter and a receiver (notshown). The transceiver 1102 is configured to perform the receiving andsending functionality described above for an responder node which, asnoted above includes receiving from a peer node via a GTP link a probingrequest message containing a request indication for a probing intervalrecommendation for probing the GTP link and sending to the peer node aprobing response message containing a probing interval recommendationdetermined by the responder network node 1100. The intervalrecommendation determining module 1108 is configured to perform theinterval recommendation determining functionality described above inrelation to a responder node, which includes determining a probinginterval recommendation for probing the GTP link.

The interval recommendation determining module 1108 is implemented atleast partially in the memory 1106 in the form of software or(computer-implemented) instructions executed by the processor(s) 1104within the responder network node 1100 or distributed across two or morenodes (e.g., the responder network node 1100 and another node). Inanother example, the receiving and sending functionality described abovein relation to a responder node is instead implemented in the form ofsoftware or (computer-implemented) instructions executed by theprocessor(s) 1104 in combination with the transceiver 1102 within theresponder network node 1100 or distributed across two or more nodes(e.g., the responder network node 1100 and another node). In yet anotherexample, the processor(s) 1104 includes one or more hardware components(e.g., Application Specific Integrated Circuits (ASICs)) that providesome or all of the receiving, sending and/or interval recommendationdetermining functionality described above. In another embodiment, theprocessor(s) 1104 include one or more hardware components (e.g., CentralProcessing Units (CPUs)), and some or all of the receiving, sendingand/or interval recommendation determining functionality described aboveis implemented in software stored in, e.g., the memory 1106 and executedby the processor 1004 in combination with the transceiver 1102. In yetanother embodiment, the processor(s) 1104 and memory 1106 formprocessing means (not shown) configured to perform the receiving,sending and/or interval recommendation determining functionalitydescribed above.

FIGS. 9A-B show a variant for each of the originator and respondernetwork node examples of FIGS. 8A-B, denoted respectively as originatoraccess node 1200, and responder network node 1300. Each of the nodes1200, 1300 includes a transceiver 1202, 1302 and circuitry containing(computer-implemented) instructions which when executed by one or moreprocessor(s) 1204, 1300 cause their respective node 1200, 1300 toperform some or all of their respective sending, receiving, intervalsetting/interval recommendation determining functionality describedabove. In yet another variant, the circuitry includes the respectivememory 1206, 1306 and processor(s) 1204, 1304 which, similarly to theexample originator and responder network nodes 1000, 1100 of FIGS. 8A-Bmay be implemented in many different ways. In one example, the memories1206, 1306 contain instructions which, when executed, cause therespective nodes 1200, 1300 to perform some or all of their respectivesending, receiving, interval setting/interval recommendation determiningfunctionality described above. Other implementations are possible.

OTHER EMBODIMENTS

The following is also noted in accordance with other contemplatedembodiments.

According to a broad aspect, there is provided a method for a networknode for probing GTP links operable to carry data traffic between thenetwork node and peer nodes in a communication network. The methodincludes at the network node receiving a probing request messageoriginating from a first peer node via a GTP link where the probingrequest message contains a request indication for a probing intervalrecommendation for probing the GTP link. The method also includes inresponse to the probing request message received, determining a probinginterval recommendation for probing the GTP link. The method alsoincludes sending a probing response message to the first peer node viathe GTP link where the probing response message contains the probinginterval recommendation.

In some embodiments, sending a probing response message includes sendinga number of successive probing response messages to the first peer nodewhere each successive probing response message contains the probinginterval recommendation determined. In other embodiments, the probingresponse message contains at least one parameter associated with one ofthe probing request message, the probing response message and the GTPlink.

In yet other embodiments, the probing interval recommendation is acurrent probing interval and the method further includes receiving asubsequent probing request message originating from the first peer nodevia the GTP link where the subsequent probing request message contains arequest indication for a probing interval recommendation for probing theGTP link. In these embodiments, in response to the subsequent probingrequest message received, the method further includes determining asubsequent probing interval recommendation for probing the GTP linkwhere the second probing interval recommendation is different from thecurrent probing interval. The method also includes sending a subsequentprobing response message to the first peer node via the GTP link wherethe subsequent probing response contains the subsequent probing intervalrecommendation. In yet other embodiments, the method further includesrepeating the acts of receiving, determining and sending for each of aplurality of probing request messages received from the first peer node.

In yet other embodiments, the probing interval recommendation is a firstprobing interval recommendation and the GTP link is a first GTP link,and the method further includes receiving a probing request messageoriginating from a second peer node via a second GTP link where theprobing request message from the second peer node contains a requestindication for a probing interval recommendation for probing the secondGTP link. In these embodiments, the method further includes in responseto the probing request received from the second peer node, determining asecond probing interval recommendation for probing the second GTP linkwhere the second probing interval recommendation is determinedindependently of the first probing interval recommendation. The methodfurther includes sending a probing response message to the second peernode via the second GTP link where the probing response message for thesecond peer node contains the second probing interval recommendation. Inyet other embodiments, the method further includes repeating the acts ofreceiving, determining and sending for probing the second GTP link withthe second peer node for each of a plurality of probing request messagesreceived from the second peer node.

In yet other embodiments, determining a probing interval recommendationfor probing the GTP link includes determining a probing intervalrecommendation based on at least one of a condition at the network nodeand a capability of the network node. In yet other embodiments,determining a probing interval recommendation for probing the GTP linkincludes determining a probing interval recommendation based on leastone of a capability of the network node, a congestion level at thenetwork node, a number of probe messages processed at the network node,a CPU utilization level at the network node, a traffic level for the GTPlink, a type for the GTP link, and a number of current GTP links at thenetwork node. In yet other embodiments, the GTP link comprises one of aGTP path, one or more GTP tunnels, one or more GTP-U tunnels and one ormore GTP-C tunnels.

In yet other embodiments, the probing request message includes a GTP-UEcho request and the probing response message includes a GTP-U Echoresponse and wherein the probing interval recommendation is included inone of an Information Element and a private extension of the GTP-U Echoresponse. In yet other embodiments, the probing request message includesa TWAMP Session-Sender test packet and the probing response messageincludes a TWAMP Session-Reflector test packet and wherein the probinginterval recommendation is included in a field of the TWAMPSession-Reflector packet.

In yet other embodiments, the request indication for a probing intervalrecommendation for probing the GTP link includes one of a flag, aprivate extension, a current probing interval value, a current probingmethod value, and a probing interval Information Element. In yet otherembodiments, the probing interval recommendation includes one of aprobing interval value and a probing method value indicative of aprobing interval value.

In another broad aspect, there is provided another method for a networknode for probing GTP links operable to carry data traffic between thenetwork node and peer nodes in a communication network. The methodincludes at the network node sending a probing request message to afirst peer node via a GTP link where the probing request messagecontains a request indication for a probing interval recommendation forprobing the GTP link. The method further includes receiving a probingresponse message from the first peer node via the GTP link where theprobing response message contains a probing interval recommendationdetermined by the first peer node.

In some implementations, the method further includes setting a probinginterval for the GTP link based on the probing interval recommendationdetermined by the first peer node. In other embodiments, the methodfurther includes setting a probing interval for the GTP link based onthe probing interval recommendation determined by the first peer nodeand at least one of a condition at the network node and a capability ofthe network node. In yet other embodiments, the method further includessetting a probing interval for the GTP link based on the probinginterval recommendation determined by the first peer node and at leastone of a capability of the network node, a congestion level at thenetwork node, a number of probe messages processed at the network node,a CPU utilization level at the network node, a traffic level for the GTPlink, a type for the GTP link, and a number of current GTP links at thenetwork node.

In some implementations, the method further includes sending asubsequent probing request message to the first peer node via the GTPlink at a time based on the probing interval set. In otherimplementations, the method further includes sending a subsequentprobing request message to the first peer node via the GTP link at atime based on the probing interval set, after receiving a number ofsuccessive probing response messages from the first peer node. In otherimplementations, the probing response message contains at least oneparameter associated with one of the probing request message, theprobing response message and the GTP link.

In yet other implementations, the probing interval recommendationcontained in the probing response message is a first probing intervalrecommendation and the method further includes sending a subsequentprobing request message to the first peer node via the GTP link wherethe subsequent probing request message contains a request indication fora probing interval recommendation for probing the GTP link. In thoseimplementations, the method further includes receiving a subsequentprobing response message from the first peer node via the GTP link wherethe subsequent probing response message contains a subsequent probinginterval recommendation determined by the first peer node and differentfrom the first probing interval recommendation. In yet otherimplementations, the method further includes repeating the acts ofsending a probing request message to the first peer node and receiving aprobing response message from the first peer node based on the probinginterval recommendation contained in the probing response message.

In yet other implementations, the probing interval recommendationcontained in the probing response message is a first probing intervalrecommendation and the GTP link is a first GTP link and the methodfurther includes sending a probing request message to a second peer nodevia a second GTP link wherein the probing request message to the secondpeer node contains a request indication for a probing intervalrecommendation for probing the second GTP link. The method furtherincludes receiving a probing response message from the second peer nodevia the second GTP link where the probing response message from thesecond peer node contains a second probing interval recommendationdetermined by the second peer node independently of the first probinginterval recommendation. In yet other implementations, the methodfurther includes repeating the acts of sending and receiving for probingthe second GTP link with the second peer node based on the secondprobing interval recommendation.

In yet other implementations, the probing interval recommendation isdetermined based on at least one of a capability of the first peer node,a congestion level at the first peer node, a number of probe messagesprocessed at the first peer node, a CPU utilization level at the firstpeer node, a traffic level for the GTP link, a type for the GTP link,and a number of current GTP links at the first peer node. In yet otherimplementations, the GTP link comprises one of a GTP path, one or moreGTP tunnels, one or more GTP-U tunnels and one or more GTP-C tunnels. Inyet other implementations, the probing request message includes a GTP-UEcho request and the probing response message includes a GTP-U Echoresponse and wherein the probing interval recommendation determined isincluded in one of an Information Element and a private extension of theGTP-U Echo response. In yet other implementations, the probing requestmessage includes a TWAMP Session-Sender test packet and the probingresponse message includes a TWAMP Session-Reflector test packet andwherein the probing interval recommendation determined is included in afield of the TWAMP Session-Reflector packet. In yet otherimplementations, the request indication for a probing intervalrecommendation for probing the GTP link includes one of a flag, aprivate extension, current probing interval value, a current probingmethod value, and a probing interval Information Element. In yet otherimplementations, the probing interval recommendation determined includesone of a probing interval value and a probing method value indicative ofa probing interval value.

In another broad aspect, there is provided a network node configured toprobe GTP links operable to carry data traffic between the network nodeand peer nodes in a communication network, where the network nodeincludes circuitry containing instructions which, when executed, causethe network node to perform any of the method embodiments describedabove. In some embodiments, the network node includes a radio accessnode (e.g. an eNodeB or WLAN Access Point) or an S-GW node.

In yet another broad aspect, there is provided a non-transitory computerreadable memory configured to store executable instructions for anetwork node and where the network node is configured to probe GTP linksoperable to carry data traffic between the network node and peer nodesin a communication network, and where the executable instructions whenexecuted by a processor cause the network node to implement any of theabove method embodiments described above.

In yet another broad aspect, there is provided a network node configuredto probe GTP links operable to carry data traffic between the networknode and peer nodes in a communication network, where the network nodeincludes a receiver for receiving a probing request message originatingfrom a first peer node via a GTP link where the probing request messagecontains a request indication for a probing interval recommendation forprobing the GTP link. The network node also includes an intervalrecommendation determining module for determining a probing intervalrecommendation for probing the GTP link in response to the probingrequest message received. The network node also includes a transmitterfor sending a probing response message to the first peer node via theGTP link where the probing response message contains the probinginterval recommendation determined.

In yet another broad aspect, there is provided a network node configuredto probe GTP links operable to carry data traffic between the networknode and peer nodes in a communication network, where the network nodeincludes a transmitter for sending a probing request message to a firstpeer node via a GTP link, where the probing request message contains arequest indication for a probing interval recommendation for probing theGTP link. The network node also includes a receiver for receiving aprobing response message from the first peer node via the GTP link,where the probing response message contains the probing intervalrecommendation determined by the first peer node. In someimplementations, the network node also includes an interval settingmodule for setting a current probing interval based on the probinginterval recommendation determined by the first peer node.

It will be appreciated by persons skilled in the art that the principlesdescribed herein are not limited to what has been particularly shown anddescribed herein above. In addition, unless mention was made above tothe contrary, it should be noted that all of the accompanying drawingsare not to scale. A variety of modifications and variations are possiblein light of the above teachings which are limited only by the followingclaims.

1. A method for a network node (220) for probing General Packet RadioSystem (GPRS) Tunneling Protocol (GTP) links operable to carry datatraffic between the network node (220) and peer nodes in a communicationnetwork, the method comprising at the network node (220): receiving(S402) a probing request message (222A-C) originating from a first peernode via a GTP link, the probing request message (222A-C) containing arequest indication for a probing interval recommendation for probing theGTP link; in response to the probing request message received,determining (S404) a probing interval recommendation for probing the GTPlink; and sending (S406) a probing response message (224A-C) to thefirst peer node via the GTP link, the probing response message (224A-C)containing the probing interval recommendation.
 2. The method of claim 1wherein sending a probing response message (224A-C) comprises sending anumber of successive probing response messages (224A-C) to the firstpeer node, each containing the probing interval recommendation.
 3. Themethod of claim 1 wherein the probing response message (224A-C) containsat least one parameter associated with one of the probing requestmessage (222A-C), the probing response message (224A-C) and the GTPlink.
 4. The method of claim 1 wherein the probing intervalrecommendation is a current probing interval, the method furthercomprising: receiving (S402) a subsequent probing request message(222A-C) originating from the first peer node via the GTP link, thesubsequent probing request message (222A-C) containing a requestindication for a probing interval recommendation for probing the GTPlink; in response to the subsequent probing request message received,determining (S404) a subsequent probing interval recommendation forprobing the GTP link, the second probing interval being different fromthe current probing interval; and sending (S406) a subsequent probingresponse message (224A-C) to the first peer node via the GTP link, thesubsequent probing response (224A-C) containing the subsequent probinginterval recommendation.
 5. The method of claim 1 further comprisingrepeating the acts of receiving (S402), determining (S404) and sending(S406) for each of a plurality of probing request messages (222A-C)received from the first peer node.
 6. The method of claim 1 wherein theprobing interval is a first probing interval and the GTP link is a firstGTP link, the method further comprising: receiving (S402) a probingrequest message (222A-C) originating from a second peer node via asecond GTP link, the probing request message (222A-C) from the secondpeer node containing a request indication for a probing intervalrecommendation for probing the second GTP link; in response to theprobing request received from the second peer node, determining (S404) asecond probing interval recommendation for probing the second GTP link,the second probing interval recommendation being determinedindependently of the first probing interval recommendation; and sending(S406) a probing response message (224A-C) to the second peer node viathe second GTP link, the probing response message for the second peernode containing the second probing interval recommendation.
 7. Themethod of claim 6 wherein the method further comprises repeating theacts of receiving (S402), determining (S404) and sending (S406) forprobing the second GTP link with the second peer node for each of aplurality of probing request messages (222A-C) received from the secondpeer node.
 8. The method of claim 1 wherein determining a probinginterval recommendation for probing the GTP link comprises determining aprobing interval recommendation based on at least one of a capability ofthe network node, a congestion level at the network node, a number ofprobe messages processed at the network node, a CPU utilization level atthe network node, a traffic level for the GTP link, a type for the GTPlink, and a number of current GTP links at the network node.
 9. Themethod of claim 1 wherein the GTP link comprises one of a GTP path, oneor more GTP tunnels, one or more GTP-U tunnels and one or more GTP-Ctunnels.
 10. The method of claim 1 wherein the probing request message(222A-C) comprises a GTP-U Echo request and the probing response message(224A-C) comprises a GTP-U Echo response and wherein the probinginterval recommendation is included in one of an Information Element anda private extension (228A) of the GTP-U Echo response.
 11. The method ofclaim 1 wherein the probing request message comprises a Two-Way ActiveMeasurement Protocol (TWAMP) Session-Sender test packet and the probingresponse message comprises a TWAMP Session-Reflector test packet andwherein the probing interval recommendation is included in a field ofthe TWAMP Session-Reflector packet.
 12. The method of claim 1 whereinthe request indication for a probing interval recommendation for probingthe GTP link comprises one of a flag, a private extension, a currentprobing interval value, a current probing method value, and a probinginterval Information Element.
 13. The method of claim 1 wherein theprobing interval recommendation comprises one of a probing intervalvalue and a probing method value indicative of a probing interval value.14. A network node (220) configured to probe General Packet Radio System(GPRS) Tunneling Protocol (GTP) links operable to carry data trafficbetween the network node (220) and peer nodes in a communicationnetwork, the network node (220) comprising circuitry containinginstructions which, when executed, cause the network node (220) to:receive a probing request message (222A-C) originating from a first peernode via a GTP link, the probing request message (222A-C) containing arequest indication for a probing interval recommendation for probing theGTP link; in response to the probing request message received, determinea probing interval recommendation for probing the GTP link; and send aprobing response message (224A-C) to the first peer node via the GTPlink, the probing response message (224A-C) containing the probinginterval recommendation.
 15. The network node (220) of claim 14 whereinto send a probing response message (224A-C) to the first peer node, theinstructions are further configured to cause the node (220) to send anumber of successive probing response messages (224A-C) to the firstpeer node, each containing the probing interval recommendation.
 16. Thenetwork node of claim 14 wherein the probing response message (224A-C)contains at least one parameter associated with one of the probingrequest message (222A-C), the probing response message (224A-C) and theGTP link.
 17. The network node (220) of claim 14 wherein the probinginterval recommendation is a current probing interval, the instructionsbeing further configured to cause to node (220) to: receive a subsequentprobing request message (222A-C) originating from the first peer nodevia the GTP link, the subsequent probing request message (222A-C)containing a request indication for a probing interval recommendationfor probing the GTP link; in response to the subsequent probing requestmessage received, determine a subsequent probing interval recommendationfor probing the GTP link, the second probing interval recommendationbeing different from the current probing interval; and send a subsequentprobing response message (224A-C) to the first peer node via the GTPlink, the subsequent probing response (224A-C) containing the subsequentprobing interval recommendation.
 18. The network node (220) of claim 14wherein the instructions are further configured to cause the node (220)to receive, determine and send for each of a plurality of probingrequest messages (222A-C) received from the first peer node.
 19. Thenetwork node (220) of claim 14 wherein the probing intervalrecommendation is a first probing interval recommendation and the GTPlink is a first GTP link, the instructions being further configured tocause the node (220) to: receive a probing request message (222A-C)originating from a second peer node via a second GTP link, the probingrequest message (222A-C) from the second peer node containing a requestindication for a probing interval recommendation for probing the secondGTP link; in response to the probing request received from the secondpeer node, determine a second probing interval recommendation forprobing the second GTP link, the second probing interval recommendationbeing determined independently of the first probing intervalrecommendation; and send a probing response message (224A-C) to thesecond peer node via the second GTP link, the probing response message(224A-C) for the second peer node containing the second probing intervalrecommendation.
 20. The network node (220) of claim 19 wherein theinstructions are further configured to cause the node (220) to receive,determine and send for probing the second GTP link with the second peernode for each of a plurality of probing request messages (222A-C)received from the second peer node.
 21. The network node (220) of claim14 wherein to determine a probing interval recommendation for probingthe GTP link, the instructions are further configured to cause the node(220) to determine a probing interval recommendation based on at leastone of a capability of the network node, a congestion level at thenetwork node, a number of probe messages processed at the network node,a CPU utilization level at the network node, a traffic level for the GTPlink, a type for the GTP link, and a number of current GTP links at thenetwork node.
 22. The network node (220) of claim 14 wherein the GTPlink comprises one of a GTP path, one or more GTP tunnels, one or moreGTP-U tunnels and one or more GTP-C tunnels.
 23. The network node (220)of claim 14 wherein the probing request message comprises a GTP-U Echorequest and the probing response message comprises a GTP-U Echo responseand wherein the probing interval recommendation is included in one of anInformation Element and a private extension (228A) of the GTP-U Echoresponse.
 24. The network node (220) of claim 14 wherein the probingrequest message comprises a Two-Way Active Measurement Protocol (TWAMP)Session-Sender test packet and the probing response message comprises aTWAMP Session-Reflector test packet, and wherein the probing intervalrecommendation is included in a field of the TWAMP Session-Reflectorpacket.
 25. The network node (220) of claim 14 wherein the requestindication for a probing interval for probing the GTP link comprises oneof a flag, a private extension, a current probing interval value, acurrent probing method value, and a probing interval InformationElement.
 26. The network node (220) of claim 14 wherein the probinginterval recommendation comprises one of a probing interval value and aprobing method value indicative of a probing interval value.
 27. Anon-transitory computer readable memory configured to store executableinstructions for a network node (220), the network node (220) configuredto probe General Packet Radio System (GPRS) Tunneling Protocol (GTP)links operable to carry data traffic between the network node and peernodes in a communication network, the executable instructions whenexecuted by a processor cause the network node (220) to: receive aprobing request message (222A-C) originating from a first peer node viaa GTP link, the probing request message (222A-C) containing a requestindication for a probing interval recommendation for probing the GTPlink; in response to the probing request message received, determine aprobing interval recommendation for probing the GTP link; and send aprobing response message (224A-C) to the first peer node via the GTPlink, the probing response message (224A-C) containing the probinginterval recommendation.